Liquid crystal display panel

ABSTRACT

A transverse electric field type liquid crystal display panel includes a pair of substrates opposed with a liquid crystal layer interposed therebetween. A plurality of sub-pixels having at least one curved portion in a display area are provided in a matrix on one side of the pair of substrates, and a pair of electrodes having at least one curved portion are formed in the plurality of sub-pixels. A light shield layer shielding a non-display area positioned on an outer peripheral side of the display area and between the plurality of sub-pixels is formed on the other side of the pair of substrates. The light shield layer of the non-display area is formed in a shape in which the outermost peripheral side of the display area is rectangular.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/341,758, filed on Nov. 2, 2016, which is a continuation ofU.S. patent application Ser. No. 14/689,379, filed on Apr. 17, 2015,issued as U.S. Pat. No. 9,507,223 on Nov. 29, 2016 which application isa continuation of U.S. patent application Ser. No. 14/048,113, filedOct. 8, 2013, issued as U.S. Pat. No. 9,041,884 on May 26, 2015, whichapplication is a continuation of U.S. patent application Ser. No.13/330,150, filed on Dec. 19, 2011, issued as U.S. Pat. No. 8,582,060 onNov. 12, 2013, which contains subject matter related to Japanese PatentApplication JP 2009-138908 filed in the Japan Patent Office on Jun. 10,2009, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present disclosure relates to a transverse electric field typeliquid crystal display panel, and more particularly, to a transverseelectric field type liquid crystal display panel with a high apertureratio, in which a shape of a sub-pixel has a curved portion and an endportion of a display area is rectangular.

Liquid crystal display panels have the characteristics of being lightweight, thin, and having low power consumption as compared with CRTs(cathode ray tubes), and thus are used in various electronic apparatusesas displays. Through the use of a rubbing-processed alignment film, aliquid crystal display panel changes the direction of liquid crystalmolecules arranged in a predetermined direction by an electric field,thereby changing a transmittance ratio or a reflectance ratio of lightto display an image.

As a method of applying an electric field to a liquid crystal layer ofthe liquid crystal display panel, there are a longitudinal electricfield manner and a transverse electric field manner. In the longitudinalelectric field type liquid crystal display panel, a substantiallylongitudinal electric field is applied to liquid crystal molecules by apair of electrodes disposed with a liquid crystal layer interposedtherebetween. As the longitudinal electric field type liquid crystaldisplay panel, a TN (Twisted Nematic) mode, a VA (Vertical Alignment)mode, an MVA (Multi-domain Vertical Alignment) mode and the like areknown. In the transverse electrical field type liquid crystal displaypanel, a pair of electrodes insulated from each other are provided onthe inside of one of a pair of substrates disposed with a liquid crystallayer interposed therebetween, and a substantially transverse electricfield is applied to the liquid crystal molecules. As the transverseelectric field type liquid crystal display panel, one of an IPS(In-Plane Switching) mode in which a pair of electrodes are notoverlapped in the plan view, and one of an FFS (Fringe Field Switching)mode in which a pair of electrodes are overlapped are known.

In the IPS mode liquid crystal display panel, a pair of electrodes, suchas a pixel electrode and a common electrode, is formed in a tooth shapeto engage with each other in a state of electrical insulation, and atransverse electric field is applied to the liquid crystal between thepixel electrode and the common electrode. The IPS mode liquid crystaldisplay device has an advantage of a wide view angle wider than that ofthe longitudinal electric field type liquid crystal display device.

In the FFS mode liquid crystal display panel, a pair of electrodes suchas an upper electrode and a lower electrode are provided on layersdifferent from each other with an insulating film interposedtherebetween, a slit-shaped aperture is provided in the upper electrode,and a substantially transverse electric field passing through theslit-shaped aperture is applied to a liquid crystal layer. Since the FFSmode liquid crystal display panel is capable of obtaining a wide viewangle and has an effect whereby image contrast is capable of beingimproved, recently, it has come into widespread use.

In the transverse electric field type liquid crystal display panel, theslit-shaped aperture (case of FFS mode) formed in the upper electrode oran aperture (case of IPS mode, hereinafter, also referred to as“slit-shaped aperture”) formed between both electrodes in the plan viewextends to be slightly inclined with respect to a rubbing direction, toenable rotation of the liquid crystal molecules in the same direction.In a color display liquid crystal display panel, it is possible toreduce the change of color caused by the view angle, by a multi-domainprocess of dividing the inclination angle with respect to the rubbingdirection of the slit-shaped aperture into two positive and negativeareas. However, since it is difficult to form an electric field in adesired direction at an end portion of the slit-shaped aperture, whenthe slit-shaped apertures in the extending directions different fromeach other are separated, the number of end portions of the slit-shapedapertures increases and as a result the aperture ratio is lowered.

In a liquid crystal display panel disclosed in Japanese UnexaminedPatent Application Publication No. 2002-014374 or Japanese UnexaminedPatent Application Publication No. 2008-083386, a slit-shaped apertureis provided with a curved portion, the multi-domain process is achievedand the aperture ratio is increased by connecting slit-shaped aperturesextending in different directions.

SUMMARY

When the slit-shaped aperture provided with the curved portion is formedin the sub-pixel demarcated by a signal line and a scanning linelongitudinally and transversely extending in a linear shape like thetransverse electric field type liquid crystal display panel disclosedJapanese Unexamined Patent Application Publication No. 2002-014374 orJapanese Unexamined Patent Application Publication No. 2008-083386, thewidth of a part of the electrodes becomes large. Accordingly, anelectrode area, which is away from the slit-shaped aperture and does notparticularly contribute to the generation of an electric field fordriving the liquid crystal, is created, and thus the aperture ratiodecreases.

For this reason, as disclosed in Japanese Patent No. 3194127, the signallines and the scanning lines are curved to be parallel to theslit-shaped aperture provided with the curved portion such that theshape of the electrode is the same shape as that of the slit-shapedaperture provided with the curved portion, and thus the sub-pixel hasthe same curved shape as that of the slit-shaped aperture. A liquidcrystal display panel 50 disclosed in Japanese Patent No. 3194127 willbe described with reference to FIG. 8A, FIG. 8B, and FIG. 8C. FIG. 8A,FIG. 8B, and FIG. 8C are a plan view and partially enlarged views of theliquid crystal display panel disclosed in Japanese Patent No. 3194127.

As shown in the partially enlarged view of FIG. 8A of one sub-pixel, theliquid crystal display panel 50 is the FFS mode liquid crystal displaypanel, the upper electrode 51 is provided with a slit-shaped aperture52, and the upper electrode 51 and the lower electrode 53 have curvedshapes similarly to the slit-shaped aperture 52. An array substrate ARhas an extending portion 57 provided with a driver terminal 55 and aflexible printed board terminal 56. A color filter substrate CF can bebonded to a part other than the extending portion 57 of the arraysubstrate AR. The color filter substrate CF is provided with a lightshield layer 58 forming an aperture of the display area by shielding anon-display area.

The upper electrode 51 of the sub-pixel of the display area has aslit-shaped aperture 52 extending in a direction (Y-axis direction inFIG. 8A) of the signal line 54. The scanning line 59 linearly extends ina direction (X-axis direction in FIG. 8A) intersecting with the signalline 54, and the areas surrounded with the signal lines 54 and thescanning lines 59 in the plan view constitute the sub-pixels. Theslit-shaped aperture 52 is provided with a “<”-shaped curved portion 60.The slit-shaped aperture 52 extends in the positive and negative reversedirection with respect to the rubbing process performed in the Y-axisdirection in FIG. 8A. Accordingly, in the liquid crystal display panel50, it is possible to reduce the change of color caused by the viewangle.

The upper electrode 51 and the lower electrode 53, and the signal line54 are also provided with the curved portion 61 and the curved portion62 taken along the curved portion 60 of the slit-shaped aperture 52,respectively. Accordingly, the slit-shaped aperture 52, and the upperelectrode 51 and the signal line 54 are parallel to each other, and thusthe area where the electric field becomes weak is not formed in theupper electrode 51. Therefore, the aperture ratio becomes high ascompared with the liquid crystal display panel disclosed in JapaneseUnexamined Patent Application Publication No. 2002-014374 or JapaneseUnexamined Patent Application Publication No. 2008-083386.

As described above, when the signal line 54 is provided with the curvedportion and each sub-pixel has the curved portion, the light shieldlayer 58 of the color filter substrate for preventing light leakagebetween the sub-pixels is also provided with the curved portion takenalong the signal line 54, as described in Japanese Patent No. 3194127.However, as shown in the partially enlarged views of FIG. 8B and FIG.8C, the innermost peripheral side of the light shield layer 58 of thenon-display area forming the aperture end portion of the display area isalso provided with the curved portion, and thus there is a problem thatthe periphery of the display area is jagged. The problem occurs also inthe case of the IPS mode liquid crystal display panel.

It is desirable to provide a transverse electric field type liquidcrystal display panel with a high aperture ratio in which an apertureend of a display area is rectangular in a transverse electric field typeliquid crystal display panel in which a shape of each-sub-pixel has acurved portion.

According to an embodiment of the present disclosure, there is provideda transverse electric field type liquid crystal display panel includinga pair of substrates opposed with a liquid crystal layer interposedtherebetween, wherein a plurality of sub-pixels having at least onecurved portion in a display area are provided in a matrix on one side ofthe pair of substrates, and a pair of electrodes having at least onecurved portion are formed in the plurality of sub-pixels, wherein alight shield layer shielding a non-display area positioned on an outerperipheral side of the display area and between the plurality ofsub-pixels is formed on the other side of the pair of substrates, andwherein the light shield layer of the non-display area is formed in ashape in which the outermost peripheral side of the display area isrectangular.

In the transverse electric field type liquid crystal display panel ofthe present disclosure, the plurality of sub-pixels having at least onecurved portion are provided in a matrix in the display area on one sideof the pair of substrates, that is, an array substrate side, and theplurality of sub-pixels are provided with a pair of electrodes having atleast one curved portion. With such a configuration, the area which isnot used for display becomes narrow, and thus it is possible to obtainthe transverse electric field type liquid crystal display panel with ahigh aperture ratio and high brightness. However, the light shield layershielding the non-display area positioned on the outer peripheral sideof the display area and between the plurality of sub-pixels is formed onthe other side of the pair of substrates, that is, a color filtersubstrate. However, the innermost peripheral side of the light shieldlayer of the non-display area forming the aperture end portion of thedisplay area is also provided with the curved portion, and thus theperiphery of the display area becomes jagged.

According to the liquid crystal display panel of the embodiment of thepresent disclosure, the light shield layer of the non-display area isformed in the shape in which the outermost peripheral side of thedisplay area is rectangular. Accordingly, the aperture end portion ofthe display area can be made rectangular, and thus the periphery of thedisplay area becomes smooth, which is visually satisfactory.

In the liquid crystal display panel according to an embodiment of thepresent disclosure, signal lines and scanning lines may be formed on oneside of the pair of substrates, and the signal lines and the scanninglines may be curved along the shape of the sub-pixels.

When the sub-pixel is provided with the curved portion, one side of thesignal line and the scanning line is curved according to the shape ofthe curved sub-pixel, and the other side of the signal line and thescanning line linearly extends. For this reason, according to the liquidcrystal display panel according to the embodiment of the presentdisclosure, the pair of electrodes can be disposed throughout the areabetween the signal lines and between the scanning lines, and thus it ispossible to improve the aperture ratio. According to the embodiment ofthe present disclosure, it is possible to obtain the effect of thepresent disclosure even in any of a case where the sub-pixels are curvedin a column direction along the signal lines and a case where thesub-pixels are curved in a line direction along the scanning lines.

In the liquid crystal display according to the embodiment of the presentdisclosure, it is preferable that when the outermost side of thesub-pixel positioned on the outermost peripheral side of the displayarea is an inner angle side, the light shield layer of the non-displayarea is formed to pass through a curved point of the inner angle side ofthe sub-pixel.

According to the embodiment of the present disclosure, it is possible tomake the periphery of the display area smooth while preventing theaperture ratio from decreasing. When the outermost side of the sub-pixelpositioned on the outermost peripheral side of the display area is theinner angle side, and when the shielding is performed to the side closerto the display area than the curved point of the inner angle sidepositioned on the outermost side of the display area by the light shieldlayer of the non-display area, the jaggedness does not occur in theperiphery of the display area, but the bright area of the sub-pixels iswidely shielded, which is not preferable. Similarly, when the sidecloser to the non-display area side than the curved point of the innerangle side positioned on the outermost side of the display area iscovered by the light shield layer of the non-display area, the outerangle side of the signal lines and the scanning lines is exposed to thedisplay area side, and the jaggedness occurs in the periphery of thedisplay area, which is not preferable.

In the liquid crystal display panel according to the embodiment of thepresent disclosure, it is preferable that when the outermost side of thesub-pixel positioned on the outermost peripheral side of the displayarea is an outer angle side, the light shield layer of the non-displayarea is formed to pass through an end point of the outer angle side ofthe sub-pixel.

In the present disclosure, “the end point of the outer angle side” meansan angled portion of the outer angle side of angled portions of fourcorners of each sub-pixel. In the liquid crystal display deviceaccording to the embodiment of the present disclosure, it is possible tomake the periphery of the display area smooth while preventing theaperture ratio from decreasing. When the outermost side of the sub-pixelpositioned on the outermost peripheral side of the display area is theouter angle side, and when the shielding is performed to the displayarea over the end point of the outer angle side positioned on theoutermost side of the display area by the light shield layer of thenon-display area, the jaggedness does not occur in the periphery of thedisplay area, but the bright area of the sub-pixels is widely shielded,which is not preferable. Similarly, when the side closer to thenon-display area side than the end point of the outer angle sidepositioned on the outermost side of the display area is shielded by thelight shield layer of the non-display area, the inner angle side of thesignal lines and the scanning lines is exposed to the display area side,and the jaggedness occurs in the periphery of the display area, which isnot preferable.

In the liquid crystal display panel according to the embodiment of thepresent disclosure, it is preferable that the sub-pixels of theoutermost peripheral side of the display area have an area wider thanthat of the other sub-pixels.

When the sub-pixels of the outermost peripheral side of the display areaare covered by the light shield layer of the non-display area, the areaof the aperture portion of the sub-pixels of the outermost peripheralside of the display area becomes small. According to the liquid crystaldisplay device of the embodiment of the present disclosure, thesub-pixels of the outermost peripheral side of the display area have thearea wider than that of the other sub-pixels. Accordingly, even when thesub-pixels of the outermost peripheral side of the display area arecovered by the light shield layer of the non-display area, the area ofthe aperture portion can be the same as that of the other sub-pixels,and thus the sub-pixels of the outermost peripheral side of the displayarea are prevented from being dark.

In the liquid crystal display panel of the embodiment of the presentdisclosure, it is preferable that a dummy pixel is formed on the outsideof the display area, and the dummy pixel is in an inactive state.

The dummy pixel simulates the same configuration as that of thesub-pixel. For example, the dummy pixel may serve as an electrostaticprotective circuit. In the transverse electric field type liquid crystaldisplay panel, on the further outer peripheral side of the sub-pixels ofthe outermost peripheral side of the display area, liquid crystal of theoutside thereof is not driven, and thus a domain (alignment defect)occurs. According to the embodiment of the present disclosure, thedomain occurring on the further outer peripheral side of the sub-pixelsof the outermost peripheral side of the display area can be made into anunrecognizable state by the light shield layer of the non-display area.For this reason, according to the liquid crystal display panel of theembodiment of the present disclosure, even when the dummy pixel isprovided, the deterioration of the display image quality of thesub-pixels of the outermost peripheral side of the display area isreduced.

In the liquid crystal display panel of the embodiment of the presentdisclosure, it is preferable that the pair of electrodes are formed of alower electrode, an insulating film formed on the lower electrode, andan upper electrode formed on the insulating film and provided with aslit-shaped aperture curved along the shape of the sub-pixel.

According to the liquid crystal display panel of the embodiment of thepresent disclosure, it is possible to obtain the FFS mode liquid crystaldisplay panel having the effect of the present disclosure.

In the liquid crystal display panel of the embodiment of the presentdisclosure, it is preferable that the pair of electrodes are opposed toeach other in a pectinated shape, and are curved along the shape of thesub-pixel.

According to the liquid crystal display panel of the embodiment of thepresent disclosure, it is possible to obtain the IPS mode liquid crystaldisplay panel having the effect of the present disclosure.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view illustrating a display area of a liquid crystaldisplay panel of a first embodiment.

FIG. 2 is an enlarged view of a part II shown in FIG. 1.

FIG. 3 is a cross-sectional view taken along the line shown in FIG. 2.

FIG. 4 is a cross-sectional view taken along the line IV-IV shown inFIG. 2.

FIG. 5 is a plan view illustrating a liquid crystal display panel of asecond embodiment.

FIG. 6 is a plan view illustrating a liquid crystal display panel of athird embodiment.

FIG. 7 is a plan view illustrating a liquid crystal display panel of afourth embodiment.

FIG. 8A to FIG. 8C are plan views illustrating a display area of aliquid crystal display panel of the related art.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings, exemplifying a case of an FFS modetransverse electric field type liquid crystal display panel. However,the following embodiments do not intend that the present disclosure islimited to the description, and the present disclosure may be applied tovarious modifications in the same manner without deviating from thetechnical concept described in the Claims. In the drawings fordescription in the specification, the scales are different according tolayers and members in order that the layers and members are recognizableon the drawings, and they are not necessarily proportional to the actualsize.

First Embodiment

A configuration of main parts of a liquid crystal display panel 10 of afirst embodiment will be described with reference to FIG. 1 to FIG. 4.The liquid crystal display panel 10 operates in the FFS mode, and has aplurality of sub-pixels 11 arranged in a matrix. In the liquid crystaldisplay panel 10, a liquid crystal layer LC is interposed between anarray substrate AR and a color filter substrate CF as shown in FIG. 3and FIG. 4. A base substrate of the array substrate AR is a firsttransparent substrate 12 formed of transparent insulating glass, quartz,plastic, or the like. On the first transparent substrate 12, scanninglines 13 formed of metal such as opaque aluminum and molybdenum areformed in the X-axis direction (line direction) shown in FIG. 2 on theside coming in contact with the liquid crystal layer LC. A gateelectrode G is provided to extend from the scanning line 13, forexample, on the left downside of each sub-pixel 11.

A transparent gate insulating film 14 formed of silicon nitride orsilicon oxide is laminated to cover the scanning line 13 and the gateelectrode G. A semiconductor layer 15 formed of amorphous silicon orpolycrystalline silicon is formed on the gate insulating film 14overlapping with the gate electrode G in the plan view. A plurality ofsignal lines 16 formed of metal such as aluminum and molybdenum isformed on the gate insulating film 14 in the Y-axis direction (columndirection) shown in FIG. 1. Each of areas partitioned by the scanninglines 13 and the signal lines 16 is a sub-pixel area. A source electrodeS is provided to extend from the signal line 16, and the sourceelectrode S comes in partial contact with the surface of thesemiconductor layer 15.

A drain electrode D simultaneously formed of the same material as thatof the signal line 16 and the source electrode S is provided on the gateinsulating film 14, and the drain electrode D is provided close to thesource electrode S to come in partial contact with the surface of thesemiconductor layer 15. Since one substantially square pixel (not shown)is configured by three sub-pixels of R (red), G (green), and B (blue),the sub-pixels 11 trisecting the pixel are rectangular in which the sideof the scanning line 13 is a short side and the side of the signal line16 is a long side. A thin film transistor TFT that is a switchingelement is configured by the gate electrode G, the gate insulating film14, the semiconductor layer 15, the source electrode S, and the drainelectrode D, and each sub-pixel 11 is provided with the TFT.

A transparent passivation film 17 formed of, for example, siliconnitride or silicon oxide is laminated to cover an exposed part of thesignal line 16, the thin film transistor TFT, and the gate insulatingfilm 14. An interlayer resin film 18 formed of a transparent resinmaterial such as photoresist is laminated to cover the passivation film17. A lower electrode 19 formed of a transparent conductive materialsuch as ITO (Indium Thin Oxide) and IZO (Indium Zinc Oxide) is formed tocover the interlayer resin film 18. A contact hole 20 passing throughthe first interlayer resin film 18 and the passivation film 17 andreaching the drain electrode D is formed, and the lower electrode 19 andthe drain electrode D are electrically connected to each other throughthe contact hole 20. For this reason, the lower electrode 19 operates asa pixel electrode.

A transparent interlayer insulating film 21 formed of, for example,silicon nitride or silicon oxide is laminated to cover the lowerelectrode 19. An upper electrode 22 formed of a transparent conductivematerial such as ITO or IZO is formed to cover the interlayer insulatingfilm 21. In the liquid crystal display device 10 of the firstembodiment, the upper electrode 22 is connected (not shown) to a commonline at a peripheral portion of the display area, and operates as acommon electrode. In the liquid crystal display device 10, the upperelectrode may operate as a pixel electrode, and the lower electrode mayoperate as a common electrode.

As shown in FIG. 2, the upper electrode 22 is provided with a pluralityof slit-shaped apertures 23. The slit-shaped apertures 23 are formed byexposing, developing, and then etching a photoresist material appliedonto the surface of the upper electrode 22 according tophotolithography. A specific shape and the like of the slit-shapedapertures 23 will be described later. A first alignment film 24 formedof polyimide is laminated to cover the upper electrode 22. A liquidcrystal direction alignment process, that is, a rubbing process isperformed on the first alignment film 24 in the Y-axis direction (adirection substantially parallel to the extending direction of thesignal line 16) shown in FIG. 2.

A base substrate of the color filter substrate CF is a secondtransparent substrate 25 formed of transparent insulating glass, quartz,plastic, or the like. The second transparent substrate 25 is providedwith a light shield layer 26 and a color filter layer 27 passingdifferent colors of light (e.g., R (red), G (green), and B (blue)) foreach sub-pixel. The light shield layer 26 is formed of a part formed tooverlap with the scanning line 13, the signal line 16, the TFT, and thedrain electrode D in the plan view, and a part covering a non-displayarea of the second transparent substrate 25 to form the apertures of thedisplay area. The display area is an area where an image recognizable bya user is substantially displayed.

The color filter layer 27 is formed in the area of the sub-pixel 11where the light shield layer 26 is not formed. An overcoat layer 28formed of, for example, a transparent resin material such as photoresistis laminated to cover the light shield layer 26 and the color filterlayer 27. The overcoat layer 28 is formed to planarize a leveldifference caused by the color filter layer 27 for a different color andto prevent impurities flowing out of the light shield layer 26 or thecolor filter layer 27 from entering the liquid crystal layer LC. Asecond alignment film 29 formed of polyimide is formed to cover theovercoat layer 28. A rubbing process in the reverse direction to thefirst alignment film 24 is performed on the second alignment film 29.

The array substrate AR and the color filter substrate CF formed asdescribed above are opposed to each other, a seal member (not shown) isprovided in the periphery of both substrates to bond and combine bothsubstrates, thereby obtaining a liquid crystal display panel 10according to the first embodiment. A spacer (not shown) for keeping theliquid crystal layer LC to be a predetermined thickness is formed on thecolor filter substrate CF. The array substrate AR has an extendingportion 32 in which a driver terminal 30 and a flexible printed boardterminal 31 are provided. A part other than the extending portion 32 ofthe array substrate AR is adhered to the color filter substrate CF.

In the configuration described above, when the TFT is turned on andvoltage is applied between the lower electrode 19 and the upperelectrode 22, an electric field occurs between both electrodes 19 and 22to change an alignment direction of liquid crystal molecules of theliquid crystal layer LC. Accordingly, optical transmissivity of theliquid crystal layer LC is changed to display an image. Assistantcapacitance is incidentally formed by the lower electrode 19, the upperelectrode 22, and the interlayer insulating film 21. When the TFT isturned off, the electric field between both electrodes 19 and 22 is keptfor a predetermined time.

The slit-shaped apertures 23 formed in the upper electrode 22 will bedescribed with reference to FIG. 2. In the FFS mode liquid crystaldisplay panel 10, the electric field occurs due to a potentialdifference between the upper electrode 22 and the lower electrode 19positioned under the slit-shaped apertures 23. The electric field occurssubstantially in parallel to the face of the array substrate AR, and thedirection of the electric field in the plan view is a perpendicular linedirection of an edge of the slit-shaped aperture 23. Since the electricfield direction is different from the electric field direction of thelong side part of the slit-shaped aperture 23 at both ends of theslit-shaped aperture 23, a reverse twist domain occurs. In the reversetwist domain, since normal displaying is not performed, a decrease of anaperture ratio is caused.

Around both ends of the slit-shaped apertures 23, there are areas forclosing the slit-shaped apertures 23, and thus the aperture ratiofurther decreases. Since the sub-pixel 11 in the liquid crystal displaypanel 10 of the embodiment is longitudinal, the number of end portionsof the slit-shaped apertures 23 when the slit-shaped apertures 23 extendin the transverse direction is greatly increased. In the liquid crystaldisplay panel 10 of the embodiment, as shown in FIG. 2, the extendingdirection of the slit-shaped aperture 23 is the extending direction(Y-axis direction shown in FIG. 2) of the signal lines 16, thus thenumber of end portions of the slit-shaped apertures 23 is reduced, andthe aperture ratio is prevented from being lowered.

The extending direction of the slit-shaped apertures 23 is inclined by apredetermined angle (e.g., about 5° to about 15°) with respect to thedirection of the rubbing process. Accordingly, the liquid crystalmolecules can be rotated in the same direction. When all the slit-shapedapertures 23 are rotated clockwise or anticlockwise, the liquid crystalmolecules can be twisted. Accordingly, a phenomenon of changing a coloraccording to a view direction occurs. The reason is because retardationin the external view is changed according to the direction of viewingthe liquid crystal molecules. To reduce the phenomenon, the liquidcrystal display panel 10 of the embodiment is provided with two domainsin which the extending direction of the slit-shaped apertures 23 isinclined in the positive and negative reverse direction with respect tothe clockwise direction. That is, it is the multi-domain process.

When the slit-shaped apertures 23 of the domains in different alignmentdirections are separated, the end portions of the slit-shaped aperture23 increases. Accordingly, the area where the normal displaying is notperformed becomes wide, and thus the aperture ratio decreases. In theliquid crystal display panel 10 of the embodiment, as shown in FIG. 2,the slit-shaped aperture 23 is provided with a curved portion 33 in a“<” shape, and the domains in the different alignment directions areconnected. The curved portion 33 of the slit-shaped aperture 23 isformed of an inner angle side curved portion 33 a formed at an edge ofthe inner angle side, and an outer angle side curved portion 33 b formedat an edge of the outer angle side. As described above, when theslit-shaped aperture is curved in the “<” shape, the area where thenormal displaying is not performed is reduced as compared with the caseof separating the slit-shaped apertures 23. Accordingly, it is possibleto raise the aperture ratio.

For this reason, in the liquid crystal display panel 10 of theembodiment, the upper electrode 22 also extends in the extendingdirection (Y-axis direction shown in FIG. 2) of the signal line 16 andis formed in the “<” shape by providing a curved portion 34. The curvedportion 34 of the upper electrode 22 is also formed of an inner angleside curved portion 34 a formed at an edge of the inner angle side, andan outer angle side curved portion 34 b formed at an edge of the outerangle side. The signal line 16 is also provided with a curved portion 35to be formed in the “<” shape. The curved portion 35 of the signal line16 is also formed of an inner angle side curved portion 35 a formed atan edge of the inner angle side, and an outer angle side curved portion35 b formed at an edge of the outer angle side. Accordingly, since thesignal line 16 and the upper electrode 22 are parallel to theslit-shaped aperture 23, the area where the electric field strengthbecomes weak in the liquid crystal display panel described in JapanesePatent No. 3194127 does not occur. Therefore, it is possible to preventbrightness from decreasing.

In the liquid crystal display panel 10 of the embodiment, each sub-pixel11 formed of the area surrounded by the signal lines 16 and the scanninglines 13 in the plan view has a shape curved in the “<” shape, by theconfiguration described above. A curved point of the inner angle side ofeach sub-pixel 11 is Ea, and an angled portion of the outer angle sideamong angled portions of four corners of each sub-pixel 11 is an endpoint Eb.

Since the signal line 16 is provided with the curved portion 35, thelight shield layer 26 overlapping with the signal line 16 of the displayarea is also curved along the curved portion 35 of the signal lien 16.However, as shown in FIG. 1, the light shield layers 26 a and 26 b ofthe non-display area forming the aperture of the rectangular displayarea are not curved, and are linearly formed. That is, in the liquidcrystal display panel 10 of the first embodiment, in the sub-pixel 11 a(right end in FIG. 2) in which the outermost side of the sub-pixel 11positioned on the outermost peripheral side of the display area is theinner angle side, the light shielding is performed over the curved pointEa of the inner angle side of the sub-pixel 11 a to the display areaside by the light shield layer 26 a of the non-display area. In thesub-pixel 11 b (left end in FIG. 2) in which the outermost side of thesub-pixel 11 positioned on the outermost peripheral side of the displayarea is the outer angle side, the light shielding is performed over theend point Eb of the outer angle side of the sub-pixel 11 b to thedisplay area side by the light shield layer 26 a of the non-displayarea.

Accordingly, the signal line 16 formed on the sub-pixel 11 a and 11 bsides of both ends of the display area is shielded by the light shieldlayers 26 a and 26 b of the non-display area, the jaggedness does notoccur in the display area, and it is possible to make the periphery ofthe display area smooth.

Second Embodiment

Next, a liquid crystal display panel 10A according to a secondembodiment will be described with reference to FIG. 5. In FIG. 5, thesame reference numerals and signs are given to the same configuration asthe liquid crystal display panel 10, and the detailed description isomitted. The liquid crystal display panel 10A of the second embodimentis different in size of the light shield layer 26 forming the aperturesof the display area from that of the first embodiment.

In the liquid crystal display panel 10 of the first embodiment, as shownin FIG. 2, in the sub-pixel 11 a (right end in FIG. 2) in which theoutermost side of the sub-pixel 11 positioned on the outermostperipheral side of the display area is the inner angle side, the lightshielding is performed over the curved point Ea of the inner angle sideof the sub-pixel 11 a to the display area side by the light shield layer26 a of the non-display area. In the sub-pixel 11 b (left end in FIG. 2)in which the outermost side of the sub-pixel 11 positioned on theoutermost peripheral side of the display area is the outer angle side,the light shielding is performed over the end point Eb of the outerangle side of the sub-pixel 11 b to the display area side by the lightshield layer 26 b of the non-display area. With such a configuration,even when there is superposition misalignment between the arraysubstrate AR and the color filter substrate CF, or production error, itis possible to make the periphery of the display area smooth.

However, in the liquid crystal display panel 10 of the first embodiment,the light shielding is performed on the display area by the light shieldlayers 26 a and 26 b of the non-display area. Accordingly, the area ofthe sub-pixel of the outermost peripheral side is reduced, and thus thesub-pixel becomes darker than the sub-pixels of the other parts. In theliquid crystal display panel 10A of the second embodiment, thejaggedness does not occur in the periphery of the display area and thesub-pixel of the outermost peripheral side becomes the brightest.

In the liquid crystal display panel 10A of the second embodiment, whenthe sub-pixel positioned on the outermost peripheral side of the displayarea is the sub-pixel 11 a in which the outermost side is the innerangle side, the light shield layer 26 a of the non-display area isformed to pass through the curved point Ea of the inner angle side ofthe sub-pixel 11 a. In addition, when the sub-pixel positioned on theoutermost peripheral side of the display area is the sub-pixel 11 b inwhich the outermost side is the outer angle side, the light shield layer26 a of the non-display area is formed to pass through the end point Ebof the outer angle side of the sub-pixel.

According to the liquid crystal display panel 10A of the secondembodiment with such a configuration, the signal lines 16 are shieldedby the light shield films 26 a and 26 b. Accordingly, the jaggednessdoes not occur in the periphery of the display area. According to theliquid crystal display panel 10A of the second embodiment, when thedisplay area side is further covered by the light shield layers 26 a and26 b of the non-display area, the jaggedness does not occur in theperiphery of the display area. However, the aperture area of thesub-pixel is reduced, and thus the sub-pixel becomes dark. On thecontrary, when the light shield layers 26 a and 26 b of the non-displayarea are retreated to the non-display area, the aperture area of thesub-pixel is increased to be bright. However, the signal line 16 appearsin the periphery of the display area, and thus the jaggedness occurs.

According to the liquid crystal display panel 10A of the secondembodiment shown in FIG. 5, the jaggedness does not occur in theperiphery of the display area, and it becomes the brightest state. Inliquid crystal display panel of the second embodiment, the jaggednessdoes not occur in the periphery of the display area even in any of thesub-pixels 11 a and 11 b of the outermost peripheral side, and itbecomes the brightest state, but both are not necessarily in such astate. That is, only one side of the sub-pixels 11 a and 11 b of theoutermost peripheral side may employ the same configuration as the caseof the liquid crystal display panel 10A of the second embodiment, andthe other side may employ the same configuration as the case of theliquid crystal display panel 10 of the first embodiment.

Third Embodiment

Next, a liquid crystal display panel 10B according to a third embodimentwill be described with reference to FIG. 6. In FIG. 6, the samereference numerals and signs are given to the same configuration as theliquid crystal display panel 10 of the first embodiment, and thedetailed description is omitted. The liquid crystal display panel 10B ofthe third embodiment is different from that of the first embodiment inregard to the size of the sub-pixels 11 a and 11 b of the outermostperipheral side of the display area.

In the liquid crystal display panel 10 of the first embodiment, as shownin FIG. 2, the sub-pixels 11 have the same size, including thesub-pixels 11 a and 11 b of the outermost peripheral side of the displayarea. In this respect, in the liquid crystal display panel 10B of thethird embodiment, as shown in FIG. 6, a width of the sub-pixels 11 otherthan both ends of the display area is WM, a width of the sub-pixel 11 aof the right end is WR (WR>WM) larger than WM, and a width of thesub-pixel 11 b of the left end is WL (WL>WM) larger than WM.

With such a configuration, even when most of the display area side iscovered by the light shield layers 26 a and 26 b to solve the jaggednessof the sub-pixels 11 a and 11 b of the peripheral portion of the displayarea, the aperture areas of the sub-pixels 11 a and 11 b of theperiphery of the display area can be made equal to the aperture area ofthe sub-pixels 11 of the other parts. For this reason, according to theliquid crystal display panel 10B of the third embodiment, the jaggednessdoes not occur in the sub-pixels 11 a and 11 b of the peripheral portionof the display area, and the aperture ratio of the sub-pixels 11 a and11 b of the peripheral portion of the display area can be made equal tothe aperture ratio of the sub-pixels 11 of the other parts. Accordingly,it is possible to suppress a coloring defect or a decrease of brightnessin the peripheral portion.

Fourth Embodiment

Next, a liquid crystal display panel 10C according to a fourthembodiment will be described with reference to FIG. 7. In FIG. 7, thesame reference numerals and signs are given to the same configuration asthe liquid crystal display panel 10 of the first embodiment, and thedetailed description is omitted. The liquid crystal display panel 10C ofthe fourth embodiment is different from that of the liquid crystaldisplay panel 10 of the first embodiment in respect to the presence orabsence of a dummy pixel of the non-display area.

As shown in FIG. 7, in the liquid crystal display panel 10C of thefourth embodiment, in the non-display area covered with the light shieldlayer 26, a dummy pixel 36 is provided adjacent to the outer peripheralside of the sub-pixel of the display area. The dummy pixel 36 has thesame configuration as that of the sub-pixel 11, but is different fromthe sub-pixels 11, 11 a, and 11 b of the display area, and the electricfield is not applied to the liquid crystal layer LC. For example, thedummy pixel 36 simulates the same configuration as that of thesub-pixel, forms a dummy pixel electrostatic protective circuit, and isused to form a protective unit against the infiltration of staticelectricity from the outside.

As described above, when the area where the electric field is appliedand the area where the electric field is not applied are adjacent at theboundary portion between the display area and the non-display area, thealignment of the display area where the electric field is applied isdisarranged, and thus a domain (alignment defect) occurs. However, inthe liquid crystal display panel 10C of the fourth embodiment, thedomain occurring on the further peripheral side of the sub-pixels 11 aand 11 b of the outermost peripheral side of the display area can bemade into a state where it is not recognizable by the light shieldlayers 26 a and 26 b of the non-display area. Accordingly, there is noadverse influence on display image quality.

In the embodiment described above, the example of the FFS mode liquidcrystal display panel in which the sub-pixel is provided with one curvedportion curved in the “<” shape is described, but the present disclosuremay be applied to an FFS mode liquid crystal display panel in which thesub-pixel is provided with a plurality of zigzag curved portions. In theembodiment described above, the example of the FFS mode liquid crystaldisplay panel in which one curved portion curved in the “<” shape alongthe signal line is formed as the sub-pixel is described, but the presentdisclosure may be applied to an FFS mode liquid crystal display panelprovided with one curved portion or a plurality of zigzag curvedportions curved in the “<” shape along the signal line is formed as thesub-pixel. In the embodiment described above, the example of the FFSmode liquid crystal display panel is described, but the presentdisclosure may be applied to the IPS mode liquid crystal display panel.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A liquid crystal display panelcomprising: a first substrate and a second substrate opposed to eachother with a liquid crystal layer therebetween; scan lines extendingoverall in a first direction; signal lines extending overall in a seconddirection crossing the first direction; a light shield layer; and aplurality of pixels that are surrounded by the scan lines and the signallines and that are arranged in a matrix, the pixels including firstpixels arranged in an outermost side among the plurality of pixels inthe first direction and second pixels arranged in other than theoutermost side among the plurality of pixels in the first direction,wherein the first pixels are entirely overlapped by the light shieldlayer, and the second pixels are not entirely overlapped by the lightshield layer.
 2. The liquid crystal display panel according to claim 1,wherein the scan lines and signal lines are overlapped by the lightshield layer.
 3. The liquid crystal display panel according to claim 2,wherein the second substrate has a first surface side that faces theliquid crystal layer, the light shield layer is disposed on the firstsurface side of the second substrate.
 4. The liquid crystal displaypanel according to claim 3, wherein the first substrate has a firstsurface side and a second surface side that faces the liquid crystallayer, the scan lines and signal lines are disposed on the secondsurface side of the first substrate.
 5. The liquid crystal display panelaccording to claim 4, wherein the second pixels are dummy pixels thatare in an inactive state.
 6. The liquid crystal display panel accordingto claim 4, wherein each of the plurality of pixels includes a lowerelectrode, an insulating film formed on the lower electrode, and anupper electrode formed on the insulating film and provided with aslit-shaped aperture having a predetermined angle with respect to thesecond direction.
 7. The liquid crystal display panel according to claim6, wherein the signal lines are bent along a shape of the pixels or theslit-shaped aperture.
 8. A liquid crystal display panel comprising: afirst substrate and a second substrate opposed to each other with aliquid crystal layer therebetween; scan lines extending overall in afirst direction; signal lines extending overall in a second directioncrossing the first direction; a plurality of pixels that are surroundedby the scan lines and the signal lines and that are arranged in amatrix, the pixels includes a first pixel arranged in an outermost pixelarea in the first direction and a second pixel arranged in other thanthe outermost pixel area; and a light shield layer disposed on aperipheral area, wherein each of the plurality of pixels includes alower electrode, an insulating film formed on the lower electrode, andan upper electrode formed on the insulating film and provided with aslit-shaped aperture having a predetermined angle with respect to thesecond direction, wherein an area that the slit-shaped aperture overlapsthe light shield layer in the first pixel is larger than an area thatthe slit-shaped aperture overlaps the light shield layer in the secondpixel.
 9. The liquid crystal display panel according to claim 8, whereinthe first substrate has a first surface side and a second surface sidethat faces the liquid crystal layer, and the scan lines and signal linesare overlapped by the light shield layer, and are disposed on the secondsurface side of the first substrate.
 10. The liquid crystal displaypanel according to claim 9, wherein the second substrate has a firstsurface side that faces the liquid crystal layer, and the light shieldlayer is disposed on the first surface side of the second substrate. 11.The liquid crystal display panel according to claim 10, wherein thesignal lines are bent along a shape of the pixels or the slit-shapedaperture.
 12. A liquid crystal display panel comprising: a firstsubstrate and a second substrate opposed to each other with a liquidcrystal layer therebetween; and a plurality of pixels arranged in afirst direction and a second direction, in a display area, each of thepixels having a lower electrode and an upper electrode that has aslit-shaped aperture having a predetermined angle with respect to thesecond direction, wherein the plurality of pixels include a first pixellocated in an outermost peripheral side of the display area and a secondpixel located in other than the outermost peripheral side, and the firstpixel has an area different from an area of the second pixel.
 13. Theliquid crystal display panel according to claim 12, further comprising:a light shield layer entirely overlapping the slit-shaped aperture ofthe first pixel.
 14. The liquid crystal display panel according to claim13, wherein the first substrate has a first surface side and a secondsurface side that faces the liquid crystal layer, and scan lines andsignal lines are overlapped by the light shield layer, and are disposedon the second surface side of the first substrate.
 15. The liquidcrystal display panel according to claim 14, wherein the signal linesare bent along a shape of the pixels or the slit-shaped aperture.
 16. Aliquid crystal display panel comprising: a first substrate and a secondsubstrate opposed to each other with a liquid crystal layertherebetween; scan lines extending overall in a first direction; signallines extending overall in a second direction crossing the firstdirection; a plurality of pixels that are surrounded by the scan linesand the signal lines and arranged in a matrix, the pixels including afirst pixel arranged in an outermost side among the plurality of pixelsin the first direction and a second pixel arranged in other than theoutermost side among the plurality of pixels in the first direction; anda light shield layer having aperture portions corresponding to each ofthe plurality of pixels, wherein an aperture portion of the first pixelis smaller than an aperture portion of the second pixel.
 17. The liquidcrystal display panel according to claim 16, wherein each of theplurality of pixels includes: a lower electrode, an insulating filmformed on the lower electrode, and an upper electrode formed on theinsulating film and provided with a slit-shaped aperture having apredetermined angle with respect to the second direction, and wherein anentire area of the slit-shaped aperture is overlapped with the lightshield layer.
 18. The liquid crystal display panel according to claim17, wherein the first substrate has a first surface side and a secondsurface side that faces the liquid crystal layer, and the scan lines andsignal lines are overlapped with the light shield layer, and aredisposed on the second surface side of the first substrate.
 19. Theliquid crystal display panel according to claim 18, wherein the signallines are bent along a shape of the pixels or the slit-shaped aperture.